The present invention generally relates to anastomosis of living tissue and, more particularly, it relates to an assembly of interlocking coupling members used for compression anastomosis of tubular structures. The assembly has an improved locking feature which prevents inadvertent member dislocation after installation of a coupled assembly in a body. Also contemplated by the invention are various coupling member configurations which will facilitate placement of the assembly in a patient and enhance in the removal of a surgical instrument typically used in positioning the assembly in the patient.
A compression anastomosis coupling assembly of the type herein disclosed is typically used when a segment of a colon, or like tubular structure, is to be resected. After a section of the colon is removed, leaving opposed, proximal and distal, free ends, the coupling members are introduced, aligned and brought into locking engagement. The assembly, however, is equally suitable for use in surgical operations for connecting tubular structures in other than end to end orientation, namely, the assembly could be used to achieve either an end to side or a side to side tubal connection. The coupled members capture and compress the free ends of the colon together to effect an anastomosis by holding tissue in compression until healing occurs. Blood supply to the captured tissue is restricted. Necrosis takes place in the area of the colon captured within the assembly without causing excessive inflammation and trauma. Thereafter, the coupled assembly detaches from the anastomotic site and is expelled spontaneously through the rectum. After assembly expulsion, the colon provides an open passageway at the anastomotic site substantially as that which existed before resectioning.
Disclosure of another device used for circular anastomosis of hollow organs can be found in U.S. Pat. No. 4,598,712. This device advanced the known art field by introducing a new technique for compression anastomosis of hollow organs which, in the majority of cases, had previously been performed by using mechanical staplers for connecting tissue edges by means of metallic staples. Specifically, this device includes a three member coupling assembly having a rear locking feature wherein the inner coupling member of the device includes a conical portion which locks at the base of the intermediate coupling member locking the elements of the device. The present compression anastomosis coupling assembly further advances the art field by introducing a forward or inner locking feature in place of the known rear locking feature. The rear lock, while secure, provides a single locking arrangement whereas the forward lock provides a multiple fastening arrangement. In the forward locking configuration, the integrity of the coupled assembly is further enhanced since forces are equally distributed around the locking circumference and the locking force increases as the assembly is subjected to external forces. In yet another improved locking arrangement, there is a mechanical locking directly between each of the three coupling members. An additional feature of the new assembly which is an improvement over the known device relates to the enhanced ease in placement of the assembly in a patient. Typically, a surgical instrument, having a cutting element for cutting a member of both the known and the new devices, is commonly used with each assembly during implantation. However, the outer element of the known device does not provide a cutting guide mechanism for guiding the cutting element during device installation. The new and improved assembly includes a cutting guide on a face of one of the coupling members. Additionally, while the known device provides a cutting ring or recess on the outer element to help reduce the forces necessary to achieve cutting, the new device further reduces the required cutting forces by changing the configuration of the coupling member through which the cutting element must pass.
The primary objective of the present invention is to further advance the art field by providing a compression anastomotic coupling assembly which is an improvement over existing devices. Accordingly, herein disclosed is an implantable device which is designed and configured for greater ease in installation and which will exhibit a superior in place locking feature during healing at the site of anastomosis and thereafter be naturally expelled intact by the patient.